• Title/Summary/Keyword: George B. Post

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Associations of CYP1A1, GSTM1 and GSTT1 Polymorphisms with Lung Cancer Susceptibility in a Northern Indian Population

  • Shukla, R.K.;Tilak, A.R.;Kumar, C.;Kant, S.;Kumar, A.;Mittal, B.;Bhattacharya, S.
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.5
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    • pp.3345-3349
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    • 2013
  • Background: Susceptibility to lung cancer has been shown to be modulated by inheritance of polymorphic genes encoding cytochrome P450 1A1 (CYP1A1) and glutathione S transferases (GSTM1 and GSTT1), which are involved in the bioactivation and detoxification of environmental toxins. This might be a factor in the variation in lung cancer incidence with ethnicity. Materials and Methods: We conducted a case-control study of 218 northern Indian lung cancer patients along with 238 healthy controls, to assess any association between CYP1A1, GSTM1 and GSTT1 polymorphisms, either separately or in combination, with the likelihood of development of Lung cancer in our population. Results: We observed a significant difference in the GSTT1 null deletion frequency in this population when compared with other populations (OR=1.87, 95%CI: 1.25-2.80-0.73, P=0.002). However, GSTM1 null genotype was found associated with lung cancer in the non-smoking subgroup. (P=0.170). Conclusions: Our study showed the GSTT1 null polymorphism to be associated with smoking-induced lung cancer and the GSTM1 null polymorphism to have a link with non-smoking related lung cancer.

The Elevator, the Iron Skeleton Frame, and the Early Skyscrapers: Part 2

  • Larson, Gerald R.
    • International Journal of High-Rise Buildings
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    • v.9 no.1
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    • pp.17-41
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    • 2020
  • In Part One, I documented the evolution of the use of the elevator and the iron frame to build ever-taller buildings that would eventually be called "skyscrapers," to offset the ever-increasing cost of Manhattan real estate. By the start of the Great Depression of the 1870s in 1873, New York architects had erected two ten-storied skyscrapers. In Part Two I document the major events, designers, and buildings in New York, Chicago, and other American cities that eventually culminated in the ability to erect 20 story skyscrapers by 1890.

The Elevator, the Iron Skeleton Frame, and the Early Skyscrapers: Part 1

  • Larson, Gerald R.
    • International Journal of High-Rise Buildings
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    • v.9 no.1
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    • pp.1-15
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    • 2020
  • The evolution in the use of the elevator and the iron frame to build ever-taller buildings that would eventually be called "skyscrapers" is still somewhat shrouded in the mist of history. This two-part paper is an attempt to document the significant persons and events in that evolution, showing that these had a greater continuity than that previously recorded. In this first part, I discuss how the exploitation of the elevator in the design of buildings allowed "skyscrapers" to be built taller than the five-six story limit imposed by stairways, so that their owners could include more and more rental square footage needed to offset the increasing cost of Manhattan real estate. The use of iron framing for the interior framing in these taller buildings would reduce the amount of square footage lost to construction, thereby also increasing the rental return from the building. By the start of the Great Depression of the 1870s in 1873, New York architects had erected two ten-storied skyscrapers.

The Effect of Cucumber mosaic virus 2b Protein to Transient Expression and Transgene Silencing Mediated by Agro-infiltration

  • Choi, Min-Sue;Yoon, In-Sun;Rhee, Yong;Choi, Seung-Kook;Lim, Sun-Hyung;Won, So-Youn;Lee, Yeon-Hee;Choi, Hong-Soo;Lee, Suk-Chan;Kim, Kook-Hyung;Lomonossoff, George;Sohn, Seong-Han
    • The Plant Pathology Journal
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    • v.24 no.3
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    • pp.296-304
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    • 2008
  • The transient and rapid expression system of a foreign protein in planta is a very useful technique in biotechnology application. We have investigated optimum condition of Agrobacterium-infiltration technique in which expression level of foreign proteins were maximized without detrimental effects on plants using GFP and Cucumber mosaic virus 2b protein, which is known as an enhancer of gene expression and a suppressor of post-transcriptional gene silencing(PTGS). The optimum expression level of both RNA and protein of GFP with minimum leaf impairment was obtained at $OD_{600}$=0.2 of Agrobactrium inocula. The steady-state levels of GFP RNA and protein generally peaked at 3 and 7 days post-infiltration(dpi), respectively. In the presence of 2b, both the magnitude and duration of GFP expression was highly increased and we could detect GFP level until 17 dpi. On the other hands, the 2b-mediated higher accumulation of foreign proteins resulted in the repression of normal leaf growth, possibly due to the limitation of supply of energy or materials required for growth maintenance. Using this Agrobacterium-infiltration system with 2b and GFP, we tested a hypothesis for the threshold model of PTGS initiation. Four GFP transgenic lines of N. benthamiana, which shows different expression level of GFP were tested to determine the threshold level for PTGS initiation. Agrobacterium-infiltration of GFP into those GFP-transgenic plants resulted in the co-silencing of the transgenic GFP. It was found that very low concentration of Agrobacterium with GFP and GFP+2b($OD_{600}$=0.002-0.02) which could not phenotypically induce an additive GFP expression, was enough to trigger PTGS pathway in all GFP transgenic plants. This strongly indicates that each GFP-transgenic plant should be expressing the transgenic GFP at its own pre-determined level and there was no buffer zone of additive GFP-expression to the threshold. In other words, the PTGS seems to be immediately activated as a self-defensive mechanism if an internal balance of gene expression is broken.

Fracture resistance of implant- supported monolithic crowns cemented to zirconia hybrid-abutments: zirconia-based crowns vs. lithium disilicate crowns

  • Elshiyab, Shareen H;Nawafleh, Noor;Ochsner, Andreas;George, Roy
    • The Journal of Advanced Prosthodontics
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    • v.10 no.1
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    • pp.65-72
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    • 2018
  • PURPOSE. The aim of this in vitro study was to investigate the fracture resistance under chewing simulation of implant-supported posterior restorations (crowns cemented to hybrid-abutments) made of different all-ceramic materials. MATERIALS AND METHODS. Monolithic zirconia (MZr) and monolithic lithium disilicate (MLD) crowns for mandibular first molar were fabricated using computer-aided design/computer-aided manufacturing technology and then cemented to zirconia hybrid-abutments (Ti-based). Each group was divided into two subgroups (n=10): (A) control group, crowns were subjected to single load to fracture; (B) test group, crowns underwent chewing simulation using multiple loads for 1.2 million cycles at 1.2 Hz with simultaneous thermocycling between $5^{\circ}C$ and $55^{\circ}C$. Data was statistically analyzed with one-way ANOVA and a Post-Hoc test. RESULTS. All tested crowns survived chewing simulation resulting in 100% survival rate. However, wear facets were observed on all the crowns at the occlusal contact point. Fracture load of monolithic lithium disilicate crowns was statistically significantly lower than that of monolithic zirconia crowns. Also, fracture load was significantly reduced in both of the all-ceramic materials after exposure to chewing simulation and thermocycling. Crowns of all test groups exhibited cohesive fracture within the monolithic crown structure only, and no abutment fractures or screw loosening were observed. CONCLUSION. When supported by implants, monolithic zirconia restorations cemented to hybrid abutments withstand masticatory forces. Also, fatigue loading accompanied by simultaneous thermocycling significantly reduces the strength of both of the all-ceramic materials. Moreover, further research is needed to define potentials, limits, and long-term serviceability of the materials and hybrid abutments.

The epigenetic phenotypes in transgenic Nicotiana benthamiana for CaMV 35S-GFP are mediated by spontaneous transgene silencing

  • Sohn, Seong-Han;Choi, Min-Sue;Kim, Kook-Hyung;Lomonossoff, George
    • Plant Biotechnology Reports
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    • v.5 no.3
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    • pp.273-281
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    • 2011
  • Diverse epigenetic phenotypes are frequently found during research on transgenic plants. To understand the factors underlying such diversity, hundreds of independent 35S-GFP transgenic N. benthamiana plants were analyzed. The diverse GFP-expression phenotypes of the transgenic plants were classified into three major types based on the GFP expression patterns and their response to 35S-GFP agroinfiltration: steady-green, silenced and non-uniform phenotype. The non-uniform phenotype was further sub-divided into five minor phenotypes: variegated, red-dropped, on-silencing, partitioned and misty, according to the distribution of GFP expression on the leaves. Many of transgenic plants continuously generated diverse phenotypes over several generations despite the transgene identity. Such epigenetic GFP phenotyping was found to be the result of spontaneous transgene silencing mediated by either or both of post-transcriptional gene silencing (PTGS) and transcriptional gene silencing (TGS). This finding was verified by the detection of 21- and 24-nt small interfering RNA (siRNA) molecules, and DNA methylation in the transgenic plants that showed repeated epigenetic variation. Agroinfiltration demonstrated that irregular distribution of GFP on a leaf was the result of erratic transgene silencing, and the technique also proved to be a rapid and effective method for selecting fully silenced plants within 3 days. Furthermore, two novel phenotypes described are potential materials for in-depth investigations into the genes and mechanisms responsible for spontaneous transgene silencing.